Colours of pottery hint at power of an empire: Research

Colours of pottery hint at power of an empire: Research
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Chicago, US: Colour plays a huge role in our lives -- the hues we wear and decorate with are a way for us to signal who we are, where we're from, and what we care about. In a new study in the Journal of Archaeological Science: Reports, archaeologists compared the colours on pieces of ancient Peruvian pottery. They found that potters across the Wari empire all used the same rich black pigment to make ceramics used in rituals: a sign of the empire's influence.

The Wari empire spread over Peru's highlands and coastal areas from 600-1050 CE. "People sometimes think of the Inka as the first big empire in South America, but the Wari came first," says Luis Muro Ynonan, the study's corresponding author and a research associate and former postdoctoral scientist at the Field Museum in Chicago.

The Wari didn't leave behind a written record (or at least a system similar to the one we use now). "Since they didn't use writing, material culture -- things like pottery -- would have been an important means for conveying social and political messages," says Muro Ynonan. "The visual impact of these objects would have been super powerful." Even little details, like using the correct shade of a colour, could help signify an object's importance and legitimacy as a part of the empire.

"I remember seeing some of these Wari-influenced pots as an undergraduate archaeology student in Peru, they're fascinating," says Muro Ynonan. "The rich black colour on them is very distinctive, I've been obsessed with it for years." Muro Ynonan finally got to pursue his interest in the pigment in-depth during his postdoctoral position at the Field Museum.

He and his co-authors, including Donna Nash, an adjunct curator at the Field and associate professor and head of anthropology at the University of North Carolina Greensboro, examined pottery from different regions under Wari influence, focusing on the chemical makeup of the black pigment used.

The exact formulation of pigments varied from site to site, but overall, there was one striking similarity: many of the Wari pots examined in the study used black pigment made from minerals containing the element manganese.

"Some of the sites, specifically in northern Peru,used a different recipe for black, using iron- and calcium-rich minerals, before the Wari arrived, but after the Wari took over, they switched to the manganese-based recipes," says Muro Ynonan. The shift makes the authors suspect that the Wari empire asserted some sort of "quality control" over the pottery produced in different regions, perhaps even supplying artisans with the "correct" black pigment. "In general, black minerals are relatively easy to obtain from the valleys we looked at," says Muro Ynonan. But just any old black mineral didn't fit the official Wari look -- instead, he thinks that artisans may have been supplied with the manganese-bearing minerals from the Wari capital to produce the right shade of black.